Washington D.C.—The U.S. Food and Drug Administration (FDA) has issued the drug manufacturing giant Pfizer a warning letter, stating they have failed to rectify its testing procedures, which resulted in overdoses in over two dozen patients during a company trial. The deaths were a result of a clinical trial of Geodon, while studying the bipolar disorder in children, as reported by USA Today.

The letter, which was released on Tuesday, April 20, 2010, states that Pfizer was not properly monitoring physicians who were testing an experimental medication. The letter did not specify what the experiment drug was, but a Pfizer spokesperson reported it was Geodon. The FDA warning also followed up on issues originally cited in 2006, after 26 patients received overdoses of the psychiatric drug during a company trial. Although Pfizer retrained its physicians, three more overdoses were reported in 2007.

A new warning letter was prompted after a July 2009 inspection found that the drug maker was still failing to follow its own rules for safely conducting a study. The federal inspectors more specifically pointed out that Pfizer was “not alerting clinical investigators to new dosing problems as they occur.” In July, Pfizer reportedly responded to the FDA’s grievances, in which the FDA letter stated, “the response did not contain a detailed outline of procedures or processes that would be implemented to prevent the future occurrence of these observation.”

A Pfizer spokeswoman pointed out, “Pfizer has communicated with the FDA about our conduct of clinical trials and, over the next two weeks, will provide an outline of new and existing processes for preventing similar issues with Pfizer clinical trials.”